title: Early neural signatures of visual short-term memory.
abstract: Visual short-term memory (VSTM) relies on a distributed network including sensory-related, posterior regions of the brain and frontal areas associated with attention and cognitive control. To characterize the fine temporal details of processing within this network, we recorded event-related potentials (ERPs) while human subjects performed a recognition-memory task. The task's difficulty was graded by varying the perceptual similarity between the items held in memory and the probe used to access memory. The evaluation of VSTM's contents against a test stimulus produced clear similarity-dependent differences in ERPs as early as 156 ms after probe onset. Posterior recording sites were the first to reflect the difficulty of the analysis, preceding their frontal counterparts by about 50 ms. Our results suggest an initial feed-forward interaction underlying stimulus-memory comparisons, consistent with the idea that visual areas contribute to temporary storage of visual information for use in ongoing tasks. This study provides a first look into early neural activity underlying the processing of visual information in short-term memory.
authors.affiliation: Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, MA, USA. yigal@nmr.mgh.harvard.edu
authors.forename: Yigal
authors.initials: Y
authors.lastname: Agam
authors.forename: Joo-Seok
authors.initials: JS
authors.lastname: Hyun
authors.forename: Jared F
authors.initials: JF
authors.lastname: Danker
authors.forename: Feng
authors.initials: F
authors.lastname: Zhou
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kahana
authors.forename: Robert
authors.initials: R
authors.lastname: Sekuler
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D004569:Electroencephalography / Q000379:methods*; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology*